Geochemical Characteristics of Chang-7 Source Rocks from Well X96 in Huachi Area of Ordos Basin and Their Significance on Tight Oil Accumulation(PDF)
《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]
- Issue:
- 2016年第01期
- Page:
- 115-125
- Research Field:
- 基础地质与矿产地质
- Publishing date:
Info
- Title:
- Geochemical Characteristics of Chang-7 Source Rocks from Well X96 in Huachi Area of Ordos Basin and Their Significance on Tight Oil Accumulation
- Author(s):
- YANG Wei-wei; SHI Yu-jiang; LI Jian-feng; FENG Yuan; MA Jun; WU Kai; LUO Li-rong
- 1. Research Institute of Petroleum Exploration and Development, Changqing Oilfield Company, PetroChina, Xi’an 710021, Shaanxi, China; 2. National Engineering Laboratory for Exploration and Development of Low-permeability Oil and Gas Fields, Changqing Oilfield Company, PetroChina, Xi’an 710018, Shaanxi, China
- Keywords:
- source rock; Chang-7; geochemistry; intense hydrocarbon expulsion; volume expansion; tight oil; Ordos Basin
- PACS:
- P618.13;TE122
- DOI:
- -
- Abstract:
- Well X96 from the central lacustrine basin in Huachi area of Ordos Basin was selected to carry out a whole core analysis including organic carbon content, pyrolysis, gas chromatography-mass spectrometry of saturated hydrocarbons, kerogen observed under microscopy, etc., and comprehensive geological research on hydrocarbon expulsion, accumulation, etc., for further study on tight oil mechanism. The detailed evaluation of the geochemical characteristics of Chang-7 source rock and the relationship between high-quality source rock and tight oil accumulation using various analytical data were focused. There are three kinds of source rocks of Chang-7 from Well X96, including oil shale, mudstone and silty mudstone. The oil shale has high content of organic carbon (mean content of 15.8%), its organic matters are mainly amorphous mass with fine organic matter type (mainly type Ⅰ), and it is in the peak stage of hydrocarbon generation, so the oil shale belongs to the high-quality source rock. The high-quality source rock has high quantities of hydrocarbon generating, and the strong action of hydrocarbon generation expanding can provide enough energy for oil primary migration, which can cause strong hydrocarbon expulsion. As a result, the oil shale has low conversion rate of chloroform bitumen “A”, low ration of saturated hydrocarbon to aromatic hydrocarbon, and low yield index, and the hydrocarbon expulsion efficiency can more than 70%. Regionally, the oil shale is stably distributed at the bottom of Chang-7 with large-scale overlaying tight sandstone, the reservoirs contact with the source rocks directly. This kind of widely distributed high-quality source rock with large-scale and strong hydrocarbon expulsion is significant in the near-source tight oil accumulation providing both materials and powers.
Last Update: 2016-01-30